In the circuit shown, X is joined to Y for a long time and then X is joined to Z. The total heat produced in R2 is
LE22R12
LE22R22
LE22R1R2
LE2R22R13
Steady-state current in L=I0=ER1
Energy stored in L
=12LI02=12LE2R12
= heat produced in R2 during discharge.